Bio sensing meters applied for detecting substances contained in the blood to be analyzed, such as glucose or cholesterol normally employ a disposable sample strip. The sample strip has a reaction zone to allow blood placed thereon. The operation is controlled by a microprocessor. By execution of various methods, analysis results of the measurement are obtained.
It is normally necessary to calibrate instrumentation used in connection with test devices in order to compensate for variations from lot to lot on the sample strip manufactured. Various techniques have been suggested for encoding information into the sample strip, as disclosed by U.S. Pat. No. 5,053,199 and references cited therein, comprising electronically encoded information on a carrier having an optical bar code, a magnetizable film, a perforated strip, a fluorogens or an electrically conductive medium on a foil.
Each of such known sample strips has to be furnished with an information code, which is an additional and thus expensive effort for a disposable device.
Another conventional sensing meter uses an additional coding module or code key designed and inserted into a receptacle similar to the slot for the sample strip. While performing a measurement, the memory key has to be inserted in the sensing meter all the time for the same batch of sample strips. According to the data or the code provided by the coding module the operation method and parameter are chosen and a correct measurement result is obtained.
U.S. Pat. No. 5,366,609 and documents cited therein disclose bio sensing meters which have pluggable coding modules that enable reconfiguration of test methods and parameters employed by the meter. Threshold potentials, test times, delay periods and other pertinent test methods and constants may be entered and/or altered.
The main purpose of the coding module still is to provide information about the type of sample strip. So for each new batch of sensor strips new related information is needed.
For processing the sample measurement and the analysing routines the bio sensing meter needs certain parameter values which determine thresholds, time intervals, control numbers and calibration curve attributes.
As sample strips are disposable, preferably coding modules are disposable too. Costs for the module are therefore an important factor.